<!DOCTYPE html>
<html lang="en">
<head>
    <!--
    @Author 硕鼠
    @Date 2020/4/18 19:55
    @Version 1.0
    @Description 文件说明
  -->
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/jquery-3.4.1.min.js"></script>
    <script>
        $(function () {
            $('#btn1').click(function () {
                console.log($('#chk1').prop("checked")); //返回结果为”false“
                console.log($('#chk2').prop("checked")); //返回结果为”true“
            });

        });
    </script>
</head>
<body>
    <input id="chk1" type="checkbox">
    <!--  checked:预先选定复选框或单选按钮  -->
    <input id="chk2" type="checkbox" checked="checked">
    <button type="button" id="btn1">click me</button>
</body>
</html>